Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List

Definition: The CHMSL lamps or stop lamps are on at all times

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Retrieve DTCs.

Is the DTC retrieved as a current DTC?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

Is DTC B3903, 3950, or 3951 set?

Go to Step 5

Go to Step 4

1. Place the ignition in the ON position.
2. Ensure that the brake pedal is not applied.
3. Observe the center high mount stop lamp (CHMSL).

Is the CHMSL or stop lamps illuminated?

Go to Step 6

Go to Step 7

Test the stop lamp switch signal circuit for a short to ground. Refer to Circuit Protection - Circuit Breakers and Wiring Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 8

Test the stop lamp switch signal circuit for a short to voltage. Refer to Circuit Protection - Circuit Breakers and Wiring Repairs.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

Test the stop lamp switch signal circuit for an open or high resistance. Refer to Circuit Protection - Circuit Breakers and Wiring Repairs.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

Replace the BCM. Refer to Control Module Referencesfor BCM replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

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1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

Go to Step 2

System OK